The Earth's structure and plate tectonics

The Earth is made up of different layers:

The crust is the outer layer of the Earth. Under this is the mantle, then the outer core and the inner core in the middle.
  1. The inner core is in the centre and is the hottest part of the Earth. It is solid and made up of iron and nickel with temperatures of up to 5,500°C.
  2. The outer core is the layer surrounding the inner core. It is a liquid layer, also made up of iron and nickel.
  3. The mantle is the thickest section of the Earth at approximately 2,900 km. The mantle is made up of semi-molten rock called magma.

Demonstrating the movement of the Earth's crust and how tectonic plates interact at plate margins

The theory of plate tectonics

The crust is the outer layer of the Earth. It is a thin layer between 0 - 60 km thick. The crust is the solid rock layer upon which we live. It is either continental or oceanic. The earth's crust is broken into plates. Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. The convection currents move the plates. Where convection currents diverge near the Earth's crust, plates move apart.

Where convection currents converge, plates move towards each other. The movement of the plates, and the activity inside the Earth, is called the theory of plate tectonics.

Circular convection currents in the mantle move the plates on top - either diverging (plates move away from each other) or converging (plates move towards each other).